1. Field of the Invention
The present invention relates generally to the field of weight training devices and more particularly to barbells and dumbbells that use removable weight plates.
2. Description of the Prior Art
Free weights are used for recreational purposes in schools, rehabilitation purposes in physical therapy settings and by the general public as a tool to improve and maintain physical fitness through improved strength and increased muscle mass.
Weight lifting for improvement and maintenance of physical fitness has led to a boon not only physical fitness facilities, but also in the use of home exercise equipment. Most weight lifting regimens involve the use of free weights. Free weights consist of barbells or dumbbells and weight plates. Barbells in particular must be used in conjunction with weight plates to achieve a desired weight amount. To achieve the utility of these components, a user must use both the bar of the barbell and the weight plates, along with a means for securing the weight plates to the bar.
Weight plates traditionally consist of a disc shaped mass with a cylindrical hole placed through the center of the plate to retain the plate to the bar. Barbells have a cylindrical handle, longer than a dumbbell. Weight masses are attached at both ends of the bar, or the bar can accept weight plates at both ends to reach a desired overall mass. The weight plates are mounted on the barbell sleeve, which is a component that is permanently attached the barbell. The barbell sleeve consists of a sleeve collar and a sleeve body.
When using a barbell (or adjustable dumbbell) the free weights need to be securely fastened to the bar and easy to use. Unexpected movement of the weight plates need to be prevented for safety. Furthermore, the weight plates need to be secured in a manner that does not damage the barbell, the weight plates, or the dumbbell.
Prior art in the field seeks to achieve these ends, but heretofore has been somewhat hit or miss with regard to success. Existing products use springs, spring-loaded cams, or screws to secure themselves to the bar. Current inventions that use screws or threaded rods can damage the barbell sleeve. Prior art products are heavy and add a significant amount of weight to the barbell assembly. Current products lack durability and are often made of many small parts that can be lost or broken. Many current products use two or more inches of sleeve length in order to fasten securely, making the entire apparatus bulky. Furthermore, current inventions do not accommodate all sizes of barbell sleeves equally due to the limited range of their clamping force.
Some prior art has included locking pins (U.S. Pat. No. 4,955,603 to Becker); plunger type pieces (U.S. Pat. No. 5,346,449 to Schlagel; U.S. Pat. No. 5,911,651 to Liu; and U.S. Pat. No. 6,059,700 to Ellenburg); o-rings (U.S. Pat. No. 5,449,333 to Carter); bolts and screws (U.S. Pat. No. 6,602,169 to Patti; a rotating handle with a washer and tie-rod (U.S. Pat. No. 6,887,189 to Schiff); a ratcheting apparatus (U.S. Pat. No. 6,971,974 to Bowman et al.); an internal cam mechanism (U.S. Pat. No. 7,025,713 to Dalebout et al.); and interlocking components (U.S. Pat. No. 7,048,678).
Other prior art has used friction points similar to the present invention, but with different, more complex structures. See U.S. Pat. No. 4,893,810 to Lee; U.S. Pat. No. 5,591,109 to Strnad; U.S. Pat. No. 5,605,411 to Wilson et al; and U.S. Pat. No. 6,007,268 to Whittington et al.